Good direct-gas-fired-AHU applications include facilities/processes that have high exhaust/infiltration airflows, large open spaces with few smaller spaces, and no low-humidity-control requirements. As noted previously, direct gas-fired AHUs commonly are used in commercial kitchens. Other commercial facilities that might benefit from utilizing direct gas-fired AHUs include fitness centers/gyms, enclosed stadiums, auditoriums, large retail stores, car dealerships, airport terminals, and laboratories.

Conclusion

Though the consequences of poorly designed or installed direct gas-fired AHUs can be severe and possibly deadly, those that are well-designed and installed can provide economical, energy-efficient, and reliable service for the right applications.

Bibliography

McLean, G.W. Direct gas-fired air heating systems. (2005). Retrieved from www.hastingshvac.com/files/Direct%20Gas-Fired%20Heating%20Systems.pdf

Schultz, C.C. (2004, January). Heating large spaces. Engineered Systems. Retrieved from http://www.esmagazine.com/Articles/Feature_Article/1318da1218da8010VgnVCM100000f932a8c0

Turpin, J. (2003, September). Confusion clouds revised standards. Engineered Systems. Retrieved from http://www.esmagazine.com/Articles/Feature_Article/8d4e7dc645da8010VgnVCM100000f932a8c0

Turpin, J. (2002, September). Makeup air makes for healthier buildings. Engineered Systems. Retrieved from http://www.esmagazine.com/Articles/Feature_Article/a4e033a89bca8010VgnVCM100000f932a8c0


An engineering manager with Jacobs Engineering Inc., Vincent A. Sakraida, PE, LEED AP, has 25 years of experience designing mechanical systems for high-technology facilities, as well as extensive experience designing central-plant, laboratory-utility, and HVAC systems.